Pile fabric and method for making same



y 1962 J. R. HElKS 3,034,942

FILE FABRIC AND METHOD FOR MAKING SAME Filed Aug. 18, 1959 3,034,942 Patented May 15, 1952 3 034,942 PILE FABRIC AND METHOD FOR MAKING SAME John Robert Heiks, Wilmington, DeL, assignor to E. I. I du Pont de Nemours and Company, Wilmington, Del.,

a corporation of Delaware Filed Aug. 18, 1959, Ser. No. 834,432 4 Claims. (Cl. 154-49) This invention relates to improved pile fabrics, more particularly to novel pile fabrics having a discontinuous backing, and to processes for preparing these fabrics.

Pile fabrics are well-known and usually comprise a pile yarn tufted into a burlap backing under which may be attached .a cushioning layer. An improved pile fabric in the form of a double pleated structure comprising pleated face material superposed upon a pleated skeletal material, the materials being attached at the peaks of the folds, is described in copending application Serial No. 645,800, filed March 13, 1957. Even though these improved double pleated fabrics result in the use of less pile yarn and, therefore, are of lower cost, and also have improved compressional properties, the structure inherently possesses rowiness.

It is an object of this invention to provide a novel pile fabric structure. Another object is to provide a double pleated pile fabric which has good compressional properties and an appearance of less rowiness than such structures made heretofore. A further object is to provide a process for preparing the improved pile structure. Other objects will appear hereinafter.

The above objects are accomplished according to this invention by providing an article comprising pile yarn attached to a resilient elastomeric base layer, said layer having a plurality of linear slits throughout its area. A preferred form of the product comprises the above article wherein said pile yarn is offset ata plurality of lines corresponding to the linear slits in said base. The invention also provides a process for making the above products by slitting a pile fabric at least partially through the thickness of the elastomeric base material. When the slitting extends completely through the base, the slit sections are cemented together partially along the height of the slit. A preferred process involves the above step of slitting the pile fabric followed by cementing the slit sections together in offset relationship.

By diaphragm action as used herein is meant a distribution of a load applied to carpets and similar pile fabrics beyond the point where the load is applied in a plane normal to the direction of the applied load.

Rowiness in pile fabrics is the appearance of pile yarn in continuous parallel lines.

By linear slits is meant an opening running the length of the base material which opening, therefore, runs generally in the warp-wise direction.

Products of this invention may also be prepared by attaching pile yarn to a backing fabric using bonding techniques, obviating the addition of a third component. The bonding may be accomplished by fusing the backing fabric to the pile yarn employing dielectric heat or by temporary plasticizing with a volatile solvent. The preferred bonding is obtained when nylon pile yarn is attached to a backing fabric containing nylon fibers by localized pressure to establish points of attachment.

Another modification of products falling within the scope of this invention may be prepared by starting with foam-filled tufted carpets. These foam-filled carpets may be prepared by attaching a pile yarn throughout part of or all of its surface to an undulating foam backing layer. The undulating foam backing may be formed by a separate molding step .after which the pile yarn may be attached by cementing, or the backing may be foamed in situ in a mold of the desired shape simultaneously with the step of cementing the pile yarn to the top surface of the foam layer being formed in the mold.

FIGURE I illustrates a suitable apparatus for carrying out the bonding operation for either a two or threelayer pile fabric.

FIGURE II illustrates a pile fabric of this invention, slit in the warp-wise direction and cemented in an offset relationship.

FIGURE III illustrates a double pleated pile fabric of this invention, slit in the warp-wise direction and cemented to a backing.

The pile yarn fabric 1 and backing or skeletal fabric 2 at the point of bonding are each held in a pleated formation by the blades of drums 3 and 4 and 5 and 6, respectively, which are synchronized to apply a localized pressure at the crowns of the opposing pleats, 3 and 5. An adhesive is added to the backing fabric at roll applicator 9. After bonding, the product remains on the larger drum face while foam rubber base material 10 is applied from foam nozzle 7 to the upstanding backing fabric pleats d. The product then remains on the drum While gelling of the foam takes place during a considerable portion of the drum rotation. At the point of removal the foam is sufficiently firm so as to assure good pleat stability. Backing fabric 2 may be eliminated as desired to give the structure of FIGURE II. The pleat spacing in this operation is preferably in excess of the pleat desired in the ultimate product, and the foam, if used, is recessed in back of the fabric crowns to facilitate stretching for printing or pile cutting and compression to final dimensions.

The pile fabric taken off the drum may then be slit into sections along the warp-wise direction by any suitable cutting means. These sections are then cemented together so that the pile yarn is again evenly matched (whereby the distinct rowiness is more noticeable) or ofiset.

The sections shown in FIGURE II are cemented together partially (at 19) along the thickness of foam rubber base material 10, so that the pile yarn fabric rows 1' are offset from adjacent rows .and thereby interrupt the rowiness of conventional pile fabrics. In this structure the backing or skeletal fabric has not been used. The sections, being only partially recemented, contain linear slits 20 for reduction of the diaphragm effect.

A double-pleated pile fabric may similarly be provided. Such a fabric, shown in FIGURE III, comprises pleated pile material 1" attached to pleated backing skeletal material 2" at peaks 13 so that the intervening face and skeletal material form an enclosure elongated in a direction athwart a line joining the points of attachment. In such a fabric, the distance between points of attachment 13 is less than the distance between free peaks I5 and 15 of opposed intervening pleats. This latter distance is preferably at least twice that of the former distance for improved resilience and reduced diaphragm action. Foam rubber base material 10 having a thickness A-B may then be applied to fill the interstices of the pleats on the back of the skeleton. This pile fabric is then cut into warp-wise sections and cemented together in matched relationship (as shown in FIGURE III along linear slits 17 and a backing 18 attached thereto. Optionally these cut sections may be cemented to a backing in matched or offset relationship without cementing the cut sections together.

made by bonding a pleated nylon pile yarn warp to a pleated non-woven fabric (made from a carded blend of nylon and rayon staple fibers) and then foaming rubber latex on the back of the non-woven fabric. This double pleated fabric is then slit in the warp direction through the foam and non-woven fabric at approximately inch spacings. Then alternate strips of the slitted material are shifted by a distance the spacing of the pile loops. In this offset or staggered relationship the strips are cemented to a burlap backing to hold the offset structure permanently. This resulting offset pile fabric has improved softness because of less diaphragm action, and reduced rowiness because of the offset configuration, when compared to a double pleated fabric as defined above, which has not been slit. The novel product also reduces the transfer of an applied load in one direction normal to the applied load.

Example 11 The double pleated fabric used as starting material in Example I is slit through the foam and non-woven fabric at approximately /8 inch spacings along intersecting diagonal lines, forming diamond-shaped sections. These sections are cemented together in their original positions with rubber cement to a height of inch above the base of the structure and then laminated to a burlap fabric underneath the foam layer. The resulting pile fabric exhibits less diaphragm action than the original double pleated fabric before slitting.

Example III The back of a conventional tufted carpet (made up of nylon pile yarn tufted in parallel rows into a burlap backing) is coated with a inch thickness of foam rubber. This material is then slit through the foam and burlap fabric in inch spacings along intersecting diagonal lines, forming diamond-shaped sections. These sections are then cemented together in their original positions with rubber cement to a height of inch above the base and then laminated to a burlap fabric. A coin pressed into the pile surface moves the pile yarns for a distance of 3 pile loops from the periphery of the coin. An unslit control sample of tufted carpet with identical foam backing is observed to have pile yarn disturbed at a distance of 8 pile loops from a similarly impressed coin, demonstrating reduced diaphragm action in the pile fabric of this invention.

Example IV This example illustrates the preparation of a pile fabric which is capable of being stretched for printing or pile cutting. This product is prepared from a carpet having pleated pile yarn in parallel rows bonded to a fiat nonwoven fabric, backed with a 7 inch thickness of foam rubber cemented to the non-woven fabric. Two series of alternating slits are cut into the pile fabric, one series of which is partially recemented. The first set of slits is made from the back completely through the foam and non-woven fabric along lines midway between the points of tuft attachment to the fabric. These slits are then recemented through a distance of approximately A inch from the bottom of the foam, thereby leaving the fabric layer cut. The second set of slits is made from the back through the foam to a height of approximately inch from the bottom along lines directly below the tufted points, thereby leaving the bottom of the foam cut. No cement is applied to the latter slits. The product not only may be stretched but also may be compressed and stabilized by the addition of a second fabric layer below the foam. The novel product showed less diaphragm action when compared with the original unslit fabric.

Example V A typical bonded pile fabric is prepared by bonding continuous multi-filament nylon carpet yarn to a non- Woven fabric (made from a carded blend of 55% nylon and 45% rayon staple fibers), using a formic acid solution of 20% by weight nylon resin as a bonding agent,

which acts as a combined cement and plasticizer. The yarn and fabric are pleated over 0.036 inch blades, and both the yarn and the fabric are tipped with the cement prior to being pressed together between the blades. The resulting pile fabric contains bonds having an average pull-out strength of 11.6 pounds, compared with an average pull-out strength of 9.7 pounds for 19 different commercial carpet samples tested. The bonded carpet is then slit in a warp-wise direction, parallel with the yarn ends, at a spacing of inch between each slit, and the slitted strips are recemented together in an offset relationship with each other. A burlap backing fabric is cemented to the base to hold this offset relationship. The final product possesses greater softness and considerably less row effect than the bonded pile fabric before slitting.

Example VI A foam-filled carpet is prepared by pressing continuous multi-filament nylon yarn into a toothed form and then covering the form with a minimum inch depth of foam rubber. The form is made by pressing steel blades having a thickness of 0.036 inch and a length of inch into slots in a wood block so that the blades extend & inch above the surface of the block. The blades are offset in rows /8 inch wide, and the blades in each row have a spacing of /8 inch. Each row is covered with a inch wide strip of masking tape having adhesive on both sides, which is made to conform to the contour of the blades. Four ends of nylon pile yarn are pressed into each row and held in the pleated state by the masking tape. The foam is applied directly to the yarn and doctor-ed to form a flat foam surface at a height of V inch above the pile yarn at the crown of the pleats. When stripped from the form and turned face upward, the undulating pile yarn surface has a pleasing appearance, and the shallow loops being filled with foam have good resilience.

The foam-filled carpet is also made by cementing strips of non-woven fabric to a strip of pile yarn in conformity with the pleats and applying the foam on top of the strips so as to fill the loops and provide a flat base. The foamfilled carpet is then slit into strips as described previously and the slitted strips recemented together in offset relationship to provide a product of this invention with less rowiness than the foam-filled carpet before slitting.

Another modification includes molding the foam backing layer in an undulating configuration, then slitting this layer and attaching the pile yarn to the recemented, offset foam strips by cementing. Still another modification involves molding the foam backing in a mold having the offset configuration of the products of this invention, and, after molding, attaching the pile yarn to the molded offset foam backing to provide a product of this invention without employing a slitting step.

The backing material used in the products of this invention may be a Woven, knitted, or non-woven fabric, film, or other sheet material. It may be formed from any convenient material such as cotton, high tenacity rayon, nylon, polyethylene, and the like. It is preferred that the backing material be an elastomeric com-position composed of, for example, natural rubber, rubber latex, sponge rubber, synthetic rubber, vinyl foam, polyurethane foam, or any other material having high elasticity.

The pile yarn used in making the products of this invention may be spun staple yarn or continuous filament yarn, examples of which include those prepared from polyarnides (cg. polyhexamethylene adipamide), polycaproarnide, copolyamides and graft copolymers containing grafted salt groups, which may be obtained by reacting an unsaturated acid with a polyamide, e.g., polyhexamethylene adipamide, followed by forming the salt thereof, acrylic polymers and copolymers (e.g., polyacrylonitrile, and copolymers of acrylonitrile with methyl acrylate, vinyl chloride, vinyl pyridine, and vinylidene chloride, etc., said copolymers being prepared from monomers comprising at least about 75% acrylonitrile), polyesters such as polyethylene terephthalate and copolyesters, polyester amides, polyurethanes, vinyl polymers and copolymers such as polyvinylidene chloride and polyvinylidene cyanide, polyfluoroolefins such as polytetrafluoroethylene, polymonochlorotrifluoroethylene, polyhexafiuoropropylene and copolymers thereof, polyethylenes, and the like. For some uses, the pile yarns may be made of wool, cotton, rayon or other more conventional fibers. The yarn may be composed of a blend of two or more fibers. It is preferred to use as the pile yarn one of the many commercially available bulked synthetic yarns.

One advantage of this invention is that it provides pile fabrics which are unique both structurally and property- Wise. The products possess enhanced softness by virtue of a reduced diaphragm action. They also possess reduced rowiness, When compared with similar pile fabrics wherein each loop of pile yarn is in its conventional configuration of continuous parallel rows, and the backing is continuous (i.e., has not been slit). The transverse slitted pile fabrics made in accordance With this invention may be used to make a dimensionally stable product which is temporarily stretchable for printing.

The products of this invention are useful as rugs, carpets, upholstery, blankets, seat covers, overcoats, furs, linings for vehicles and clothing, and the like.

I claim:

1. An improved carpet structure comprising a resilient elastomeric base member having an upper surface and a lower surface, a pile fabric bonded to the upper surface of said base member, the upper surface of said base member provided with a distributed plurality of linear slits, said slits lying in planes which are substantially perpendicular to the surfaces of the base member and substantially dividing the carpet structure into a plurality of sections so that deformations in the carpet surface due to concentrated compressional loads in use are isolated and limited to substantially the area upon which the load is applied.

2. An improved carpet structure comprising a series of similar elongated strips laterally positioned adjacent one another and bonded together, each strip comprising a resilient elastomeric base member having an upper surface and a lower surface, a pile fabric bonded to the upper surface of the base member and comprising a plurality of fabric loops arranged in parallel rows, each of said strips positioned longitudinally with respect to its adjacent strips so that the rows of fabric loops in each strip are offset with respect to the rows of loops in the adjacent strips, each of said strips bonded to the adjacent strips along a Zone extending along the sides of each base member adjacent the lower surfaces only thereof so that each strip may be independently compressed without appreciably deflecting adjacent strips in the direction of compression.

3. An improved carpet structure comprising a pleated pile material superposed upon a pleated skeletal material, said materials being attached at opposing peaks of the pleats, said skeletal material bonded to an elastomeric base member having an upper and a lower surface, the base material provided with a distributed plurality of linear slits lying in planes substantially perpendicular to the main plane of the base member so that the base member is partially subdivided into a plurality of lateral sections to prevent compressional load deformation of one section from similarly deflecting adjacent sections.

4. An improved process for manufacture of carpet structures having a pile yarn fabric bonded to a resilient elastomeric base member, said fabric having a plurality of rows of pile loops, said process comprising the steps of forming a plurality of elongated substantially constant width carpet strips each having a resilient elastorneric base member bonded to a pile yarn fabric with rows of loops, assembling and aligning said strips in side by side relation with the rows of loops of each strip longitudinally offset from the rows of loops of adjacent strips, bonding said strips together in said assembled relationship along a limited narrow bottom portion only of the abutting side surfaces of the aligned base members to form a carpet structure with deflection isolating properties under compressional loads and improved surface appearance, and attaching said assembled bonded strips to a backing structure.

References Cited in the file of this patent UNITED STATES PATENTS 2,116,048 Smith May 3, 1938 2,202,663 Lahey May 28, 1940 2,702,463 Carter Feb. 22, 1955 2,750,652 Petroske June 19, 1956 FOREIGN PATENTS 145,840 Australia Mar. 24, 1952 

3. AN IMPROVED CARPET STRUCTURE COMPRISING A PLEATED PILE MATERIAL SUPERPOSED UPON A PLEATED SKELETAL MATERIAL, SAID MATERIALS BEING ATTACHED AT OPPOSING PEAKS OF THE PLEATS, SAID SKELETAL MATERIAL BONDED TO AN ELASTOMERIC BASE MEMBER HAVING AN UPPER AND A LOWER SURFACE, THE BASE MATERIAL PROVIDED WITH A DISTRIBUTED PLURALITY OF LINEAR SLITS LYING IN PLANES SUBSTANTIALLY PERPENDICULAR TO THE MAIN PLANE OF THE BASE MEMBER SO THAT THE BASE MEMBER IS PARTIALLY SUBDIVIDED INTO A PLURALITY OF LATERAL SECTIONS TO PREVENT COMPRESSIONAL LOAD DEFORMATION OF ONE SECTION FROM SIMILARLY DEFLECTING ADJACENT SECTIONS. 